Individual verification apparatus, individual verification method and computer-readable recording medium

ABSTRACT

Certain embodiments provide an individual verification apparatus, comprising: a database configured to associate a face image having the brightness and the light reception direction of an image region with the personal information of an individual; a correction section configured to carry out a correction operation using a correction amount pre-stored for image data for verification having another brightness and another light reception direction; and a verification section configured to verify the individual using the face part in the image data for verification which is corrected in at least one of brightness and light reception direction and the face image in the database.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Continuation of application Ser. No. 14/724,923filed on May 29, 2015, the entire contents of which are incorporatedherein by reference.

FIELD

Certain embodiments relate to an individual verification apparatus, anindividual verification method and a non-transitory computer-readablerecording medium.

BACKGROUND

A copier is known which is provided with an individual verificationsystem based on a camera.

The camera takes the image of a face. A plurality of face images areregistered in a database. The system verifies an individual using theimage data of the individual and the image data in the database.

The copier is placed at a certain position which is fixed with respectto a window. The angle of view of the camera is fixed.

However, the intensity of light varies. For the camera, sunlight comesfrom different directions with different intensities. The brightnessaround the copier is different at 8.00 am, 12.00 μm and 5.00 μm.

At night, an indoor illuminator, instead of the sunlight coming from thewindow, irradiates the camera. The light of an identification lampirradiates the copier from the window at night.

For the camera, the light of a light source comes from differentdirections and different angles in different seasons. The brightness ofthe light source changes with the weather.

The brightness, the contrast ratio and the light reception direction ofan installed camera change with the surroundings.

An individual verification apparatus, even when used to take the faceimage of the same person, is different in face recognition precision indifferent environments.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram illustrating an individual verificationapparatus according to a first embodiment;

FIG. 2 is a functional block diagram illustrating the correction sectionof the individual verification apparatus according to the firstembodiment;

FIG. 3A is a diagram showing an example of an image facing theindividual verification apparatus according to the first embodiment;

FIG. 3B is a diagram showing another example of an image facing theindividual verification apparatus according to the first embodiment;

FIG. 4 is a diagram illustrating the structure of a copier provided withthe individual verification apparatus according to the first embodiment;

FIG. 5 is main flowchart illustrating a verification processing carriedout by the individual verification apparatus according to the firstembodiment;

FIG. 6 is a flowchart illustrating a background image processing carriedout by the individual verification apparatus according to the firstembodiment;

FIG. 7 is a diagram showing an example of the image region of theindividual verification apparatus according to the first embodiment;

FIG. 8 is a diagram illustrating a detection method of light receptiondirection based on the individual verification apparatus according tothe first embodiment;

FIG. 9 is a flowchart illustrating a process of registering data in theface image database of the individual verification apparatus accordingto the first embodiment;

FIG. 10 is a flowchart illustrating a recognition processing carried outby the individual verification apparatus according to the firstembodiment.

FIG. 11A is a diagram showing an example of an image registered in thedatabase of the individual verification apparatus according to the firstembodiment.

FIG. 11B is a diagram showing an example of an image for verificationtaken by the camera of the individual verification apparatus accordingto the first embodiment;

FIG. 12A is a diagram showing an image for verification the brightnessof which is adjusted by the individual verification apparatus accordingto the first embodiment;

FIG. 12B is a diagram showing an image for verification the contrastratio of which is adjusted by the individual verification apparatusaccording to the first embodiment;

FIG. 12C is a diagram showing an image for verification the lightreception direction of which is adjusted by the individual verificationapparatus according to the first embodiment; and

FIG. 13 is a block diagram illustrating an individual verificationapparatus according to a second embodiment.

DETAILED DESCRIPTION

Certain embodiments provide an individual verification apparatus,including: a database configured to associate a face image with thepersonal information of an individual, wherein the face image has thefirst brightness and the first light reception direction of an imageregion in which an individual is irradiated by a light source thedirection of which varies if observed from a fixed line-of-sightdirection; a correction section configured to carry out a correctionoperation using a correction amount pre-stored for image data forverification, wherein the image data for verification has a secondbrightness and a second light reception direction; and a verificationsection configured to verify the individual using the face part in theimage data for verification and the face image stored in the database,wherein at least one of the second brightness and the second lightreception direction of the face part of the image data for verificationis corrected.

By taking those shown in accompanying drawings as an example, theindividual verification apparatus, the individual verification methodand the computer-readable recording medium are described below indetail. Moreover, in the accompanying drawings, the same parts aredenoted by the same reference signs and are not described repeatedlywhen presented again.

A First Embodiment

FIG. 1 is a block diagram illustrating an individual verificationapparatus involved in the first embodiment. An individual verificationapparatus 10 verifies, using a face image, the identity of the operatorof a copier installed indoors.

The individual verification apparatus 10 comprises a database 11, acorrection section 12, a verification section 13, a camera 14 and astorage section 15.

The database 11 associates a face image with personal ID(identification) (personal information) and stores the associated faceimage and personal ID, wherein the face image having the brightness, thecontrast ratio and the light reception direction of an image region inwhich an individual is irradiated by a light source the direction ofwhich varies if observed from a fixed line-of-sight direction.

The correction section 12 carries out a correction operation using acorrection amount pre-stored for image data for verification which hasanother brightness, another contrast ratio and another light receptiondirection.

The verification section 13 verifies an individual using the face partof the image data for verification and the face image in the database11, wherein at least one of the brightness, the contrast ratio and thelight reception direction of the face part of the image data forverification is corrected by the correction section 12.

The camera 14 separately acquires image data for registration and imagedata for verification at different timing.

The image data for registration refers to a user image which isregistered in the database 11 before a user is verified. The image datafor verification refers to a user image which is compared with the imagedata for registration that serves as a reference.

The storage section 15 stores first reference values for the brightness,the contrast ratio and the light reception direction of a backgroundimage.

The database 11 associates the face images of a plurality of personswith their personal ID information separately such as their employeenumbers.

The face image is an image taken by the camera 14 from a fixedline-of-sight direction. The fixed line-of-sight direction is theline-of-sight direction of the camera 14 fixed on the copier 100.

The face image has attribute values including brightness, contrast ratioand light reception direction.

The light source is sunlight, an indoor illuminator or an outdooridentification lamp.

FIG. 2 is a functional block diagram illustrating the correction section12. The reference signs which are illustrated above denote the samecomponents in FIG. 2.

The correction section 12 comprises a brightness adjustment portion 25and a contrast ratio adjustment portion 26.

The brightness adjustment portion 25 carries out a brightnessadjustment.

Brightness refers to brightness values of R (red), G (green) and B(blue). The brightness of a pixel represents an RGB with a brightnessvalue of, for example, eight bits. Each RGB of the plurality of pixelsin an image region has a brightness value.

The brightness adjustment portion 25 adjusts all brightness values ofRGB.

The contrast ratio adjustment portion 26 carries out a contrast ratioadjustment. Contrast ratio refers to the black-to-white ratio in animage region. Black refers to the minimal brightness, and white refersto the maximum brightness.

The correction section 12 is provided with a light reception directionadjustment portion 27 for adjusting a light reception direction.

FIG. 3A and FIG. 3B show examples of images taken in the morning and atdusk.

In the image 29A taken by the camera 14, the left-upper area is higherin brightness, and the right-lower area of the image 29A is lower inbrightness, wherein ‘higher’ and ‘lower’ are relative.

In the image 29B taken by the camera 14, the area between the right topand the right bottom is higher in brightness, and the area between theleft top and the left bottom is lower in brightness.

The light reception direction refers to the direction along whichbrightness lowers from the brightness of a high-brightness area to thatof a low-brightness area in the image data.

In the image region 29A, brightness changes in the direction from theleft-upper vertex to the right-lower vertex.

In the image region 29B, brightness changes in the horizontal direction.

The light reception direction adjustment portion 27 changes the lightreception direction of the image region 29A or 29B by inclining theperpendicular line of the horizontal centerline of the image region 29Aor 29B by an angle (degree).

The correction section 12 shown in FIG. 1 corrects the image data forregistration based on the first reference values of the backgroundimage. After completing the correction operation based on the firstreference values, the correction section 12 registers the face image thebrightness, the contrast ratio and the light reception direction ofwhich are updated to second reference values in the database 11.

The correction section 12 corrects the image data for verification usingthe second reference values.

The verification section 13 compares the face image which is stored inthe database 11 after being updated in brightness, contrast ratio andlight reception direction with the face image in the image data forverification acquired by the camera 14. The verification section 13outputs a result representing the success or failure of the faceverification according to the result of the comparison.

FIG. 4 is a diagram illustrating the structure of a copier provided withthe individual verification apparatus 10. The reference signs which aredescribed above denote the same elements in FIG. 4.

The camera 14 is fixed on the copier 100 at a position where the camera14 constitutes no obstacle to the user operating the copier 100.

The camera 14 which uses a Charge Coupled Device (CCD) image sensor or aComplementary MOS (COMOS) image sensor is positioned with its imagesensor panel facing the face of the user.

The image data for registration has its brightness, contrast ratio andlight reception direction. The image data for verification also has itsbrightness, contrast ratio and light reception direction.

The first reference values stored in the storage section 15 shown inFIG. 1 are values for correcting the face image registered in thedatabase 11. The first reference brightness, the first referencecontrast ratio and the first reference light reception direction eachhave a value of a plurality of bits.

The storage section 15 uses a storage device 20 which is a hard diskdrive or a solid state drive.

The individual verification apparatus 10 may further comprise areference value generation section 28 configured to generate firstreference values for the brightness, the contrast ratio and the lightreception direction of a background image.

Further, there is a central Processing Unit (CPU) 17, a Read Only Memory(ROM) 18, a Random Access Memory (RAM) 19 and the camera 14 on the busline 16 of the individual verification apparatus 10.

The CPU 17, the ROM 18 and the RAM 19 execute the functions of thecorrection section 12 and the verification section 13.

The CPU 17 functions as the main controller of the individualverification apparatus 10.

The RAM 19 provides a working storage area for the CPU 17.

The ROM 18 is a non-transitory computer-readable recording medium forcausing the CPU 17 to execute the following processing:

a processing of correcting the brightness, the contrast ratio and thelight reception direction of the face image and the background image inan image region;

a processing of generating first reference values for the brightness,the contrast ratio and the light reception direction of the backgroundimage;

a processing of correcting image data for registration which as itsbrightness, contrast and light reception direction based on the firstreference values of the background image, associating the face imagewith personal ID and performing a write access processing on the addressof the database 11, wherein the face image has second reference valuesin brightness, contrast ratio and light reception direction;

a processing of correcting image data for verification having anotherbrightness, another contrast ratio or another light reception directionusing the second reference values to generate corrected image data forverification; and

a processing of verifying an individual using the face part in the imagedata for verification and the face image in the database 11.

The bus line 16 is electrically connected with the controller 110 of thecopier 100.

As shown in FIG. 4, the copier 100 comprises a scanner 113, a networkinterface 114, a printer section 115 and a controller 110.

The scanner 113 scans one side of an original document G using adocument feeder 120.

The network interface 114 receives printing spool data from a PC 126through a network 125.

The printer section 115 configured to be installed and for a person toperform a user operation prints an image using four printing colors C,M, Y and K and then outputs the printed image.

The printer section 115 is equipped with four exposers 129, four imageforming portions 131C, 131M, 131Y and 131K and a belt 130.

The exposer 129 modulates an image signal into laser rays usingsemiconductor laser of each color. The belt 130 endlessly travelsanticlockwise.

The image forming portion 131 for yellow color comprises: a drum 132, acharger 133, a developer 134 and a transferring device 135.

The drum 132 is a photoconductive drum rotating along a clockwisedirection T.

The charger 133 charges the surface of the drum 132.

The developer 134 develops the electrostatic latent image on the drum132 using a toner.

The transferring device 135 primarily transfers the toner image on thedrum 132 onto the belt 130.

The image forming portion 131M for magenta color, the image formingportion 131C for cyan color and the image forming portion 131K for blackcolor are substantially structurally identical to the image formingsection 131Y.

Further, the printer section 115 has a sheet conveying mechanism 136, asecondary transferring device 137 and a fixer 138.

The sheet conveying mechanism 136 takes a sheet P from a tray 139 andguides the sheet P to the printer section 115.

The secondary transferring device 137 secondarily transfers toner imagesof four colors formed by the image forming portions 131C, 131M, 131Y and131K onto the sheet P.

The fixer 138 fixes unfixed toner images on the sheet P.

An operation panel 117 accepts a user operation.

The operation panel 117 may display the verification result of theindividual verification apparatus 10 on a window 154 on which anoperation step may also be displayed.

The controller 110 is the main controller of the copier 100. A controlsignal is transmitted between the controller 110 and the CPU 17 (shownin FIG. 1) of the individual verification apparatus 10.

Further, the individual verification method involved in the embodimentis an image processing method in the three timings carried out by theindividual verification apparatus 10.

The first timing is the generation timing of first reference values.

The second timing is the generation timing of image data forregistration in database 11.

The third timing is a verification timing at which an image forverification is used.

The individual verification method generates, during the first timing,first reference values for the brightness, the contrast ratio and thelight reception direction of the background image in the image regionphotographed by the camera 14.

The individual verification method, during the second timing, carriesout a correction operation for input of image data for registrationusing the correction section 12 based on the first reference values ofthe background image, wherein the background image is relative to theimage data for registration, in this way, a face image having secondreference values is associated with the ID of an individual and thenregistered in a database in association with the ID.

The individual verification method corrects, during the third timing,input image data for verification based on second reference values ofimage data for verification to generate corrected image data forverification.

The individual verification method verifies the individual using theface part of the image data for verification and the face image in thedatabase 11.

Next, the functional actions of the individual verification apparatus 10are described below.

The copier 100 detects a touch on the operation panel 117. The copier100 displays a dialog box on the operation panel 117. The dialog boxdisplays, for the user, an operational requirement to verify whether theuser can use the copier 100 nor not.

For example, the operation panel 117 requires the user to input a loginname and a password. Further, the operation panel 117 starts the faceverification of the individual verification apparatus 10.

As the face verification succeeds, the copier 100 takes a job.

The registration of a user in the individual verification apparatus 10before the face of the user is verified is described below.

FIG. 5 is main flowchart illustrating a verification processing carriedout by the individual verification apparatus 10.

Actions A1, A2 and A3 are equivalent to the first timing, the secondtiming and the third timing.

The first timing is, for example, 8:00 am. The second timing is, forexample, 12:00 pm. The third timing is, for example, 5:00 pm.

In Action A1, the individual verification apparatus 10 takes the imageof a background image and generates three first reference values.

FIG. 6 is a flowchart illustrating a background image processing carriedout by the individual verification apparatus 10.

In Action B1, as an imaging signal is generated which indicates thetaking of an image at 8:00 am, the camera 14 takes the image of thebackground image.

In Action B2, the individual verification apparatus 10 starts togenerate a first reference value for the brightness in the backgroundimage.

FIG. 7 is a diagram showing an example of an image region. The camera 14outputs an image region 30. The image region 30 has three areas A, B andC.

The area A is an area for face verification.

The areas B and C are both areas recognized for determining firstreference values for correction.

The reference value generation section 28 selects the area B or C as areference value generation area.

The reference value generation section 28 selects an area in which theverified object, that is, the verified individual, is not reflected.

The reference value generation section 28 selects an area, for example,a wall or ceiling, which is always photographed by the camera 14 as areference value generation area. The areas B and C are used for acomparison processing.

For example, the reference value generation section 28 calculates thebrightness of the image region 30 by averaging the values of the colorsbetween the color closest to the whitest color and the color closest tothe darkest color.

Sequentially, the reference value generation section 28 calculates afirst reference value for contrast ratio in Act B3 shown in FIG. 6.

For example, the reference value generation section 28 calculates thecontrast ratio of the image region 30 by dividing the value closest tothe lowest brightness by the value closest to the highest brightness.

Further, the reference value generation section 28 calculates a firstreference value for light reception direction in Act B4.

FIG. 8 is diagram illustrating a light reception direction detectionmethod. The image region 31 has a density because of a light source.

The reference value generation section 28 calculates a light receptiondirection by comparing the brightness values of the areas 32-35 at fourcorners of the photographed image region 31.

The reference value generation section 28 compares the brightness valuesof the areas 32 and 33. In the example shown in FIG. 8, the area 32 ishigher in brightness than the area 33. Thus, it can be determined thatin the horizontal direction of the reference value generation section28, the left part of the image region is brighter than the right part ofthe image region.

Next, the reference value generation section 28 compares the brightnessvalues of the areas 32 and 34. As the area 32 is higher in brightnessthan the area 34. Thus, it can be determined that in the verticaldirection of the reference value generation section 28, the upper partof the image region is brighter than the lower part of the image region.

Further, the reference value generation section 28 compares a firstdifference between the brightness values of the areas 32 and 33 with asecond difference between the brightness values of the areas 32 and 34.

The reference value generation section 28 determines whether or not oneof the first and the second difference is greater or smaller than theother one.

As an example, the reference value generation section 28 pre-stores dataor a formula representing the correspondence relationship between thedifference component of the first and the second difference and anoffset in the ROM 18.

An offset presenting the degree by which the light reception directionis deviated from the vertical light reception direction of the camera 14can be determined based on the result of the foregoing determination.The offset presents an in-plane quantity.

An individual can be recognized more accurately by carrying out theforegoing three processing cooperatively.

In action A2 shown in FIG. 5, before registering a user in the database11, the individual verification apparatus 10 takes an image of the user.

In action A2, the individual verification apparatus 10 compares thetaken picture (image) with the first reference values.

FIG. 9 is flowchart illustrating a process of registering a user imagecontaining a face image in the database of the individual verificationapparatus 10.

In action C1, the individual verification apparatus 10 matches thebrightness of the image with the first reference value for brightness.

The individual verification apparatus 10 matches the contrast and thelight reception direction of the image with the first reference valuesfor contrast ratio and light reception direction (actions C2 and C3).

Then, adjusted or corrected brightness, contrast ratio and lightreception direction are obtained.

In action C4, the individual verification apparatus 10 registers theuser image having second reference values in the database 11, whereinthe second reference values refer to the adjusted or correctedbrightness, contrast ratio and light reception direction.

In action A3 shown in FIG. 5, the individual verification apparatus 10carries out an individual verification. The image data for verificationobtained by the camera 14 is compared with the second reference values.

FIG. 10 is a flowchart illustrating a recognition processing carried outby the individual verification apparatus 10.

In action D1, the individual verification apparatus 10 acquires imagedata for verification from the camera 14.

FIG. 11A is a diagram showing an example of an image registered in thedatabase 11. The image is a registered image on which the processing ofaction C4 is performed.

FIG. 11B is a diagram showing an example of an image for verificationtaken by the camera 14. The image is a user picture taken at 5:00 pmwhich is relatively dark as sunlight irradiates the camera obliquely.

Sequentially, in action D2 shown in FIG. 10, the individual verificationapparatus 10 carries out a brightness adjustment based on secondreference values.

FIG. 12A is a diagram showing a brightness-adjusted image forverification. The image shown in FIG. 12A is obtained by adjusting thebrightness of the image shown in FIG. 11B.

In action D3, the individual verification apparatus 10 carries out acontrast ratio adjustment.

FIG. 12B is a diagram showing a contrast ratio-adjusted image forverification. After being adjusted in contrast ratio, the image forverification shown in FIG. 12A is adjusted in brightness and contrastratio.

In action D4, the individual verification apparatus 10 carries out alight reception direction adjustment.

FIG. 12C is a diagram showing an image for verification adjusted inlight reception direction. After being adjusted in light receptiondirection, the image for verification shown in FIG. 12A is adjusted inbrightness, contrast ratio and light reception direction.

In this way, the brightness, the contrast ratio and the light receptiondirection of the image for verification are all matched with the secondreference values.

In action D5, the individual verification apparatus 10 comparativelyverifies a face image.

In action D5, the result of the comparison is ‘matched’. In action D6,the individual verification apparatus 10 determines that theverification is successful through an ‘OK’ route.

In action D7, the individual verification apparatus 10 outputs apositive verification result.

In action D5, the result of the comparison is ‘unmatched’. In action D8,the individual verification apparatus 10 determines that theverification is failed through a ‘NG’ route. The individual verificationapparatus 10 outputs a negative verification result (action D7)

A specific user is permitted to use the copier 100. An original documentG is set through a user operation (FIG. 4), and then the copier 100copies the original document G.

As the brightness, the contrast ratio and the light reception directionof an image for verification are adjusted prior to the implementation ofan individual verification. The adjusted face image is registered in thedatabase 11. Apart from the influence caused by face data, the influencecaused by the background surrounding the individual making aregistration is also eliminated.

Even in a case where the bust picture taken by the camera 14 contains abackground, for example, a ceiling or wall, in the areas B and C outsidethe area A (FIG. 7), the face verification can be completed highlyaccurately.

The copier 100 is installed and used. The camera 14 generallyphotographs the same background.

By correcting an image using the pattern and the color of a background,the individual verification apparatus 10 improves the recognitionaccuracy.

The same individual is identified as the same individual, regardless ofthe brightness of the surroundings.

The accuracy of individual recognition is improved no matter what thecontrast ratio in a bright or dark environment is.

An individual can be correctly recognized in the morning or at dusk whensunlight comes from a different direction.

Further, the individual verification apparatus 10 may also take theimage of a background during the period of time within which the copier100 is used frequently.

The first reference values are generated based on a plurality of personsand the same time period, thereby obtaining the brightness, the contrastratio and the light reception direction which are substantially themeans of those obtained from the images of the plurality of persons.

The illumination around the copier 100 changes according to thesurroundings, for example, the illumination around the copier 100changes with sunlight during the day and an illuminator oridentification lamp at night. With the use of the individualverification apparatus 10, the recognition accuracy is guaranteed in anyenvironment. The same person can be recognized correctly in any periodof time.

Provided with an individual verification system for carrying out anindividual verification using a face image, the copier 100 achieves ahigh verification accuracy.

A Second Embodiment

In the first embodiment, when the user registers at 12:00 pm, an imagecorrection is carried out using the first reference values generated at8:00 am.

The first reference values are not used in the second embodiment. Aftercollecting information from an information server through a network, theindividual verification apparatus involved in the embodiment carries outan image correction.

FIG. 13 is a block diagram illustrating an individual verificationapparatus involved in the second embodiment. An individual verificationapparatus 40 carries out an image correction using the informationreceived from an information server 23.

The individual verification apparatus 40 is arranged on the copier 100.

The individual verification apparatus 40 is provided with a networkinterface 21. The network interface 21 receives information from theinformation server 23 through a network 22.

The individual verification apparatus 40 has a prediction correctionsection 41 (correction section) which calculates the magnitudes of thechanges of the brightness, the contrast ratio and the light receptiondirection of a face image.

The prediction correction section 41 calculates the magnitudes of thechanges based on a plurality of sample images taken by the camera 14 atfixed moments of many days.

The prediction correction section 41 calculates the line-of-sightdirection of the camera 14 based on magnitudes of changes, dateinformation and pre-stored sun position information indicating theposition of the sun at each moment.

Date information is mm/dd/yyyy. The prediction correction section 41associates date information with an image taken at the same day. Thedate information is provided by a defaulted function of the CPU 17.

The other parts of the individual verification apparatus 40 aresubstantially structurally identical to the individual verificationapparatus 10 shown in FIG. 1, if not defined particularly.

Next, the functional actions of the individual verification apparatus 40having this structure are described below.

(1) First Form

First, the prediction correction section 41 acquires, the daily azimuthand altitude of the sun, that is, the daily position information of thesun through, for example, a download operation. Alternatively, theprediction correction section 41 calculates the azimuth and the altitudeof the sun using a calculation formula in which date is used as avariable.

The prediction correction section 41 causes the camera 14 to take imagesat fixed moments, for example, causes the camera 14 to take the image ofa background at 12:00 pm every Monday.

The prediction correction section 41 stores a plurality of image samplesin the storage device 20.

For example, the prediction correction section 41 collects the sampleimages taken at 12:00 pm every Monday in several past months.

The prediction correction section 41 extracts the brightness, thecontrast ratio and the light reception direction of each sample image.For example, the prediction correction section 41 records the azimuthand the altitude of the sun at 12:00 pm on August 6.

The prediction correction section 41 accumulates daily sample data forseveral months.

The prediction correction section 41 calculates the magnitudes of thechanges occurring in brightness, contrast ratio and light receptiondirection at 12:00 pm of an unknown day.

The prediction correction section 41 determines, according to brightnessvalues of image data, that the unknown day is darker than the days inAugust.

The prediction correction section 41 determines, by comprising thealtitude of the sun in the south in august with that of the sun in thesouth on the unknown day, that the sun in the south on the unknown dayis lower in altitude.

The prediction correction section 41 determines that the time is 12:00pm on January 10 according to observation information and the positioninformation of the sun. The observation information refers to thebrightness of the sun, the south azimuth of the sun and the coordinatesof the altitude of the sun.

Further, the prediction correction section 41 detects the line-of-sightdirection of the camera 14 based on a specific date and the observationinformation. The prediction correction section 41 can detect thedirection the camera 14 faces.

Then, the individual verification apparatus 40 takes the picture of auser using the camera 14 after 12:00 pm. The taken image forregistration is input to the individual verification apparatus 40.

The individual verification apparatus 40 associates the face image datain the image data for registration with personal ID and then registersthe associated face image data and personal ID in the database 11,without correcting a background image.

Sequentially, if image data for verification is input to the predictioncorrection section 41 at 4:00 pm, then the image data for verificationis corrected using reference values for face images registered in thedatabase 11. The prediction correction section 41 generates image datafor verification.

The verification section 13 verifies the individual using the face partof the image data for verification and the face images in the database11.

Even if the line-of-sight direction of the camera 14 is unknown to theprediction correction section 41, the individual verification apparatus40 can determine the line-of-sight direction of the camera 14 accordingto the magnitude of the change in the position of the sun at a fixedposition.

As the line-of-sight direction of the camera 14 can be determinedaccording to the magnitude of the change in sun position, the predictioncorrection section 41 eliminates the influence caused by the shade of aneighboring building or by the reflection from a window on the result ofthe determination.

By using the individual verification apparatus 40, image data forverification can be corrected without using a background image.

The light reception direction mainly changes with the azimuth of the sunand the altitude of the sun with time going on. This is because sunlightenters a room from a window from different azimuths and different anglesat different time.

In a stationary type copier 100, the camera 14 is located at a fixedposition with respect to a window, facing a fixed direction. Theposition relationship between the camera 14 and the window is unchangedno matter where the copier 100 is arranged, what the season it is andwhen the time it is.

By making a determination at a determined time, for example, at 12:00pm, every other day, the individual verification apparatus 40 canpredict the direction the camera 14 faces.

Correction values can be determined according to the date on which faceimage data for registration is taken, without using the first referencevalues.

(2) Second Form

In the second form, a light source refers to an indoor illuminator.

The individual verification apparatus 40 may use a building maintenanceserver managed by a building management corporation as the informationserver 23.

The information server 23 sends the illuminance of the illuminator ineach residential room in real time. The illuminance is, or example, aLux value. A smart meter is installed in the room.

The information server 23 collects the real-time power consumption ofeach room for the individual verification apparatus 40 using a smartsystem.

The individual verification apparatus 40 receives the illuminanceinformation of the illuminator in a room from the information server 23.

The prediction correction section 41 calculates the brightness of a faceimage according to the illuminance information of the illuminator in aroom received from the information server 23.

The prediction correction section 41 calculates the contrast ratio andthe brightness of the face image in the same way.

The prediction correction section 41 calculates the light receptiondirection of the face image according to pre-stored illuminatorinformation. The illuminator information refers to the positions ofindoor illuminators, the number of indoor illuminators and theorientations of the indoor illuminators with respect to the camera 14.

The information server 23 may be an in-company server provided by acompany for the departments of the company.

The individual verification apparatus 40 acquires image data forregistration using the camera 14 at 12:00 pm.

The individual verification apparatus 40 associates the face image datain the image data for registration with personal ID and then registersthe associated face image data and personal ID in the database 11,without carrying out a correction using a background image.

The individual verification apparatus 40 corrects input image data forregistration using the reference values stored in the database 11 forface images at 4:00 pm.

The verification section 13 verifies an individual using the face partof the image data for verification and the face images in the database11.

(3) Third Form

In the third form, the change in the weather is acquired form theinformation server 23.

The prediction correction section 41 calculates the brightness, thecontrast ratio and the light reception direction of a face imageaccording to the weather information indicating a sunny day or a rainyday acquired from the information server 23.

The individual verification apparatus 40 can determine the brightnessand the contrast ratio of the face image according to the illuminationcondition and the weather information of the location where the copier100 is arranged.

After acquiring illumination information and weather information throughthe network 22, the individual verification apparatus 40 corrects theface image. The first reference values are not used during thecorrection process.

Correction values can be determined by associating registered image datafor verification with the illumination condition or weather information.

As stated above, the installation location of the copier 100, theseason, the date, the weather and the illumination condition are allstored in the individual verification apparatus 40.

It is not needed to store first reference value information or the imagein an unneeded area (the area B or C shown in FIG. 7), thus saving thecapacity of the database 11.

In this way, the individual verification apparatus reduces the influencefrom the surroundings when carrying out a face verification.

The embodiments shown in FIG. 1-FIG. 13 are merely exemplary and can bevariously modified in structure or step.

In the light reception detection method illustrated in FIG. 7, theindividual verification apparatus 10 performs a pre-processing if thebackground is not a single color different from black or a singlepattern, for example, if the ceiling or wall is coated by differentcolors.

For example, the individual verification apparatus 10 converts an imagearea (the area B or C) corresponding to a coated part into a white colorin advance.

Alternatively, the individual verification apparatus 10 carries out averification processing after the ceiling or wall is pre-covered bywhite paper.

Reference values can be highly accurately obtained according to theposition, for example, the area B or C, where correction values aredetected.

The camera 14 may be an infrared camera or a near-infrared camera.

In the foregoing embodiments, a light reception direction is representedby an angle by which the light reception direction is deviated from theperpendicular line of an image area. The light reception direction mayrepresent a solid angle using the angle of the deviation of the lightreception direction from the center of the view of the camera 14.

In the foregoing embodiments, in the detection of a light receptiondirection, the four corners of an image area are photographed and thencompared in brightness.

In the detection of a light reception direction, an image region may bedivided into grids, and then the direction along which brightnesschanges is detected. Alternatively, in the detection of a lightreception direction, an image region may be divided into a plurality ofslits, and then the direction along which brightness changes isdetected.

The camera 14 may be installed at any position of the copier 100. Thecamera 14 may be immobilized on the body of the copier by a bracket, anarm or a brace.

Holes may be set on the cover of the copier 100. The camera 14 may beimmobilized on an inner side of the cover with its image sensor panelexposed outside the cover from the hole.

The back of the image sensor panel should not face a light source.

Further, the individual verification apparatus 10 may be provided with aBluetooth (registered trademark) interface. Alternatively, a wirelesscamera may send an image to the individual verification apparatus 10according to a Bluetooth-based communication protocol.

A wireless camera fixed on the wall or ceiling of a room takes imagedata for verification and image data for registration. Installation atsuch a position, the wireless camera gets a wider view and can take animage more freely. Moreover, verification accuracy is improved.

Apparently, the wireless camera may be an installed multi-functionperipheral.

A processor-readable recording medium causes a CPU to execute variousprocessing, wherein the recording medium may be a USB memory, a CD-ROMor a DVD-ROM.

Modified embodiments cause no impairment to the priority of the imageforming apparatus, the image forming method and the recording mediuminvolved herein.

While certain embodiments have been described, these embodiments havebeen presented by way of example only, and are not intended to limit thescope of the invention. Indeed, the novel embodiments described hereinmay be embodied in a variety of other forms; furthermore, variousomissions, substitutions and changes in the form of the embodimentsdescribed herein may be made without departing from the spirit of theinvention. The accompanying claims and their equivalents are intended tocover such forms or modifications as would fall within the scope andspirit of the invention.

What is claimed is:
 1. An individual verification apparatus, comprising: a camera configured to take an individual and output an image in an image region observed from a fixed line-of-sight direction, the individual being irradiated in different brightness of light and having different directions of receiving irradiation thereto; a database configured to associate a the face image of the individual in an image for registration from the camera with unique information of the individual; and a processing unit coupled to the camera and the database, the processing unit facilitating execution of instructions to perform operations comprising: generating respective reference values for matching a brightness value and a light reception direction of an image for verification from the camera with a brightness value and a light reception of the face image of the individual, correcting the brightness value and the light reception direction of the image for verification using thus generated reference values, and verifying the individual using a face part in thus corrected image for verification and the face image stored in the database.
 2. The individual verification apparatus according to claim 1, wherein the operations by the processing unit further include: generating a reference brightness value and a reference light reception direction, respectively for a brightness value and alight reception direction of a background image in the image from the camera, correcting a brightness value and a light reception direction of the face image for registration from the camera using the reference brightness value and the reference light reception direction of the background image, registering the face image of the individual in thus corrected face image for registration in the database, and correcting the image for verification from the camera using the reference brightness value and the reference light reception direction.
 3. The individual verification apparatus according to claim 2, wherein the operations further include: generating the reference values based on a plurality of persons within the same period of time.
 4. The individual verification apparatus according to claim 1, further comprising: an interface connected with an information server, wherein the operations further include: calculating magnitudes of the changes in the brightness value and the light reception direction of the image from the camera according to a plurality of sample images at fixed moments of a plurality of days, and calculating a value of the line-of-sight direction according to the magnitudes of the changes and sun position information for each day and hour from the information server.
 5. The individual verification apparatus according to claim 1, further comprising: an interface connected with an information server, wherein the operations further include: calculating the reference value for the brightness value according to illuminance information, provided from the information server, of an illuminator in a room in which the camera is fixed, and calculating the reference value for the light reception direction according to pre-stored illuminator information in the room.
 6. The individual verification apparatus according to claim 1, further comprising: an interface connected with an information server, wherein the operations further include: calculating the reference values for the brightness value and the light reception direction of the face image according to weather information indicating a sunny day or a rainy day provided from the information server.
 7. The individual verification apparatus according to claim 1, further comprising: a stationary printer configured to permit the individual to carry out a user-based operation thereto through the verifying.
 8. An individual verification method, comprising: generating, at a first timing, a reference brightness value and a reference light reception direction, respectively for a brightness value and a light reception direction of a background image in an image region in which an individual is observed from a fixed line-of-sight direction; correcting, at a second timing, a brightness value and a light reception direction of an image for registration in which the individual is observed from the fixed line-of-sight direction, respectively using the reference brightness value and the reference light reception direction, and registering a face image of the individual in thus corrected image for registration in a database, the face image being associated with unique information of the individual; correcting, at a third timing, a brightness value and a light reception direction of an image for verification in which the individual is observed from the fixed line-of-sight direction, respectively using the reference brightness value and the reference light reception direction; and verifying the individual using a face part in thus corrected the image data for verification and the face image in the database.
 9. A non-transitory computer readable recording medium, the medium storing a program causing a processor to execute the following processing: generating, at a first timing, a reference brightness value and a reference light reception direction, respectively for a brightness value and a light reception direction of a background image in an image region in which an individual is observed from a fixed line-of-sight direction; correcting, at a second timing, a brightness value and a light reception direction of an image for registration in which the individual is observed from the fixed line-of-sight direction, respectively using the reference brightness value and the reference light reception direction, and registering a face image of the individual in thus corrected face image for registration in the database, the face image being associated with unique information of the individual; correcting, at a third timing, a brightness value and a light reception direction of an image for verification in which the individual is observed from the fixed line-of-sight direction, respectively using the reference brightness value and the reference light reception direction; and verifying the individual using a face part in thus corrected the image data for verification and the face image in the database. 